The history of Australia is the history of the land and peoples of the continental land mass and offshore territories which now comprise the Commonwealth of Australia. The Commonwealth of Australia came into existence on 1 January 1901 as a federation of former British colonies, however the human history of Australia commences with the arrival of the first ancestors of Aboriginal Australians by sea from Maritime Southeast Asia between 50,000 and 65,000 years ago, and continues to the present day multicultural democracy.

Indigenous Australians are people with familial heritage from, and/or recognised membership of, the various ethnic groups living within the territory of present day Australia prior to British colonisation. They consist of two distinct groups, which includes many ethnic groups: the Aboriginal Australians of the mainland and many islands, including Tasmania, and the Torres Strait Islanders of the seas between Queensland and Papua New Guinea, located in Melanesia. The term Aboriginal and Torres Strait Islander peoples or the person's specific cultural group, is often preferred, though the terms First Nations of Australia, First Peoples of Australia and First Australians are also increasingly common; 812,728 people self-identified as being of Aboriginal and/or Torres Strait Islander origin in the 2021 Australian Census, representing 3.2% of the total population of Australia. Of these Indigenous Australians, 91.4% identified as Aboriginal; 4.2% identified as Torres Strait Islander; while 4.4% identified with both groups. Since 1995, the Australian Aboriginal flag and the Torres Strait Islander flag have been official flags of Australia.